On one level, Inside Llewyn Davis is one of the most enjoyable movies released in the past few years. It’s funny and smart and sad. It’s remarkably well-realized, a small miracle of production design and casting. It turns out that Oscar Isaac, heretofore mostly in regrettable movies like Madonna’s W.E. and Sucker Punch (although he did have a small, powerful turn in Nicolas Refn’s Drive), is a genuinely talented musician and an actor of considerable gifts. It’s easy enough to sit back and enjoy the show, which is basically a shaggy dog (or, more accurately, cat) story that charts what might be a slightly more eventful than usual week in the life of a talented but luckless folk singer in New York’s Greenwich Village in February 1961. And the music is excellent.

Yet there are also deeper questions being teased here, and if you know something about the Greenwich Village folk scene in 1961, and how the times are about to be a’changed, then your appreciation of this Coen Brothers’ gray comedy might resound a little deeper than the “funny, smart, sad” chord just described. For Inside Llewyn Davis is also a meditation on authenticity, the mystery of creation and the mischief that is made in the lands between art and commerce.

A lot has been made about how much the fictional Llewyn Davis resembles the actual (and the late) Dave Van Ronk. The Coens haven’t tried to hide this source. They have acknowledged that Van Ronk’s book The Mayor of McDougal Street influenced their script, and even the movie’s title is a play on the 1963 album Inside Dave Van Ronk. In the film a copy of Davis’ poorly selling album - also called Inside Llewyn Davis - is glimpsed. The cover photograph is a visual quotation of the cover of Inside Dave Van Ronk, with Isaac as Davis copying a pose originally struck by Van Ronk. Davis sings songs that were in Van Ronk’s repertoire - “Hang Me, Oh Hang Me,” “Dink’s Song (Fare Thee Well)” and “Green, Green Rocky Road.” Van Ronk’s version of the latter song is also heard on the soundtrack.

But Llewyn Davis isn’t Dave Van Ronk. His voice is too pure and pretty, while Van Ronk’s instrument was wheezy and rough. And there’s a hard, blue meanness that burns in Llewyn, a refusal to compromise that’s both heroic and annoying. Some people seem to detest the character and his lack of generosity, but part of me loves Llewyn, his intransigent refusal to recognize the ultimate triviality of his best efforts and his refusal to become a total hack.

That doesn’t mean he won’t take unpleasant jobs. One of the centerpieces of Inside Llewyn Davis is a “sellout” session in which Llewyn joins his friend Jim (Justin Timberlake) and Al Cody (Adam Driver) to record a novelty song called “Please Mister Kennedy” (based in a roundabout way on Larry Verne’s 1960 novelty hit “Mr. Custer,” country singer Jim Nesbitt’s “Mr. Custer” parody “Please Mr. Kennedy” from 1961, a totally different song also called “Please Mr. Kennedy” released by Motown singer Mickey Woods, and Tom Lehrer’s 1965 ditty “Wernher von Braun”). Llewyn is disdainful of the song, but he does it for the money - and then opts for the quick session player’s payout rather than participate in back-end royalties.

But Llewyn doesn’t go the expedient route because he objects to getting rich - or at least a little bit closer to solvency - by means of a cheesy pop record. He does it because he’s in desperate need of quick cash. He’s a poor boy, actually homeless, with an album that won’t sell, a manager who has little faith in his prospects and a woman (who detests him) for whom he needs to secure an abortion. And then there’s this cat, named Ulysses, who, well never mind ….

Anyway, Llewyn goes on a journey of sorts and ends up back where he started, and all the people around him seem more facile and successful unless they’re overdosing in bathroom stalls or freezing in the backseats of pilot-less Cadillacs. His partner, Mike, the one everyone liked, no doubt the charismatic Paul McCartney to Llewyn’s sour Lennon, jumped off a bridge. All that’s left of him is Marcus Mumford’s voice on the soundtrack, and (unless I miss my guess) a photograph of a young T Bone Burnett on a mocked-up album cover.

Llewyn will never make it - he’s too bound up in his integrity, caught in the folk singer ethic that demands personal expression be channeled through songs so timeless they seem to have existed forever. He is constantly confronted with sunnier, more plastic (less authentic) versions of himself, all of whom seem to have better prospects. As the affable, slight Jim, Timberlake has never been better used in a film, and Stark Sands appears as a folk-singing soldier on leave from Fort Dix, who sings an angelically antiseptic version of Tom Paxton’s “The Last Thing On My Mind” (which was actually written in 1964, but never mind; for all its attention to detail and specificity the movie has a few poetic anachronisms - a poster for Disney’s The Incredible Journey, which wasn’t released until 1963, also provides a poignant grace note). And it’s telling that when Llewyn does come across the real thing - an autoharp-strumming head singer from Arkansas called Elizabeth Hobby (played by Nancy Blake and based no doubt on Almeda Riddle) - all he can do is insult and ridicule it.

There’s more, but I have to stop. This is a rich and wonderful film. Maybe the best the Coens have ever made.